Fuse-plug



G. W. GOODRIDGE.

FUSE PLUG. APPLICATION FILED MAY 29, |918.

1 ,330,630. Patented Feb. 10, 1920.

UNITED sTATEs PATENT oEEroE.

I GILBERT W. GOODRIDG-E, 0F BRIDGEPORT, CONNECTICUT, ASSlGNOR T0 THEBRYANT ELECTRIC COMPANY, OF BRIDGEPORT, CONNECTICUT, A. CORPORATICN OF CON- NECTICUT.

` FUSE-PLUG.

Leeaeao.

. specieation of Letters Patent.

Patented Feb., iid, i920).

IApplication led May 29, 1918. Serial No. 237,256.

To all whom t may concern:

Be it known that I, GILBERT W..G0on RIDGE, ya citizen of the United States of America, residing at Bridgeport, in the county-of Fairfield and State of Connecticut, have invented certain new and useful Improvements in F use-Plugs, of which the following is a specification.

My invention relates to fuse plugs, and the object of my invention is to provide a plug of improved construction, particularly with reference to the' fuse strip and associyated terminals and the securing means by which the use of solder or other material for securing the fuse in position may be dispensed with. Other features of improvement will also ap ear from the following description and fiom the accompanying drawing, in which-- Figure l is a broken plan of a fuse plug in which my invention is embodiedl in one form;

Fig. 2 is a broken side elevation thereof;

lFig. 3 is a vertical section on the line 3 3, Fig. 2;

Fig. t is a perspective ofthe fuse strip, detached;

Fig. 5 is a broken side elevation of a fuse plug body illustrating a modied fuse strip4 construction;

Fig. 6 is a perspective of one end of thisy modified fuse strip; l

Figs. 7 and 8 are views corresponding to Ca".

tion;

Fig. 9 is a perspective of a wire fuse einbodying my invention in modified form;

Figli() is a bottom plan of a fuse plug in which my invention is embodied in any of the forms above referred to.

Referring `to the construction shown in Figs. l to 4, the present fuse plug comprises an ginsulating bod 20 of porcelain or the like', with fuse c amber 21, and exterior lthread 22 on which is screwed the shell contact 23 of the plug. At the entering end of the plug is a'boss 24E and center contact 25. The fuse X extends from the center contact 25 through the fuse chamber to the screw shell 23. The open endof the f-hamber 21 is closed by a disk 26 of mica, held in position by a cap 27, the top flange 28 0f which over*- lies the disk 26, while its lower flan e 29 is spun beneath the shoulder 30 at the ead of' the porcelain and staked at 31 into a. notch 32 formed in the shoulder 30. In these features the construction generally resembles the plug fuses now common on the market. In such plug fuses, however, it has been heretofore the common practice to secure the fuse to the' center and shell contacts by means of solder, and this has not only necessitated the use of a large quantity of solder (with the attendant expense but has also resulted in the production o a fuse of uncertain and varying capacity, since it is impossible in a practical manufacturing operation so accurately to regulate the amount of solder used at the two contacts as to preserve a precise length of fuse strip between the points Iat which the solder is applied thereto. Moreover, it has been customary to add above the solder a plug of putty or the like, with the result that, on the blowing of the fuse, the vapors generated by the melting of the solder and the putty have an explosive action which often shatters the lplug with resulting danger to bystanders.

This is particularly Iapt to be true in plugs sealed against the escape of the gases, although for lire protection, it is highly desirable that'the plugs should be so sealed.'

tacts is predetermined with exact accuracy.

thus giving a uniform action for all plugs of the same capacity. `It has, furthermore, been found by repeated experiments that on the blowing of plugs of the present type, there is no resulting generation of eXplosive vapors and that the fuse strip melts at its calibration point without injury to the plug as a whole or danger to bystanders or surrounding equipment.

ln carrying out my invention, I have embodied it in a plug of the sealed or closed type such as is shown in my previous Patent 923,642. 1l, the center contact comprises a rivet 33,

vpreferably of brass, the sealing head 34 of As will be seen from Figs. 3 and flanges 36, between which one end of the zinc fuse strip X is received and held by tit rivets 37. The opposite end of the fuse' body 2O y inserting the terminal rivet 33 and s` reading its free end into engagement with lt e center contact ring,r 25. rlFhe contact piece 38 is then passed over the barrier i3 which separates the chamber' 21 from the well 44, and is drawn down into this well by any sultable appliance such as a hoolr eng 'ng a perforation i5 formed in the end of the terminal 38. The well 4:4: opens at its lower end through the wall of the body 20 Within the area of the threads 221. The end of the terminal 38, having been passed down through the well 4.4, is turned upward over the threads v22 :formed in the porcelain and slightly oset against the shoulder 46 at the head of the plug. When the shell 23 is screwed into position., its upper end engages the terminal 38 and not only creases the latter into the spaces between the threads 22 in the porcelain, but also engages, with its uper edge, the odset end of the terminal an thus establishes goed electrical connection therewith. After the shell 2,3 has been' screwed home and bottomed against the shoulder e6, it is held in this position by staking its lower flange 47 into recesses 48 in the porcelain at several points indicated at l.t'in Fig. l0. There is thus no danger of the shell 'backing ofi' and making poor contact with the terminals 38 oit the fuse strip.

' After the fuse `has been thus inserted, the

fuse chamber is closed by placing in position the mics, disk 26 and applying the cap 27.

in the modification illustrated in Figs. 5 and d, yl have shown the same construction, except that the terminal oit fuse X is provided with flanges 5G, thus ador-ding u v more extended bearing surface to be engaged by the screw shell 23. ln order to insert this Vinmzliied Atorni of terminal into the well., the

iianes 50 may be bent over as indicated by the netted lines 5l.

in Figs. i and 3 a further modification is illustrated, in that the terminal 38 instead of being);l 'carried up to the shoulder 46, is carried beneath the shoulder 52 at the entering end et .the plug .and is `engegecl by the lower Harige i? ot the screw shell.. Tit is, of course,

immaterial whether the 'engagement between the` terminalhd and the scnew shell 23 be made at the shoulder ab or 52, de i. i.

vuse of solder or other foreign element.

Leccese marily upon the point at which it is proposed to bottom the screw shell in its home position.

` In Fig. 9 the construction of the fuse strip is substantially the same as that shown in Fig. 4, with the exception that the fuse here comprises a thin wire of low capacity. At one end it is inserted in a tubular boss 54 extending from the inner tace of the rivet head 34, and this extension is smashed down upon the end of the fuse wire by a press which simultaneously forms a clamping tit rivet 55. The opposite end of the fuse wire is inserted between the body of the terminal 38 and its flange 39, and is held against escape by. crimping as in the case of the fuse strip X.

It'will be seen that in these several constructions, not only is' the fuse strip siiicientlyr connected to its terminal pieces, but its length between 'the terminals is accurately predetermined, and the terminals 'themselves electrically and mechanically connected to the 'plug contacts without tte t the same time, the plug is maintained closed against the escape ci llame on the blowing tained low, anl the assembly of the fuse in the plug is much more rapid than heretotore where solder has been used to connect it to the plug contacts.

Various mod-itications in the term ot the terminals and in 'the manner of fastening to I the screw shell and center contact will readily occur to those skilled in the art which do not depart from what l claim as my inventi'on.

I claim i 1. A fuse plug having insulating body 1s secured liti externally threaded at its entering end andv internally chambened to accommodate a fuse, said body being recessed to aord a lateral well opening from the fuse chamber to the exterior of plug, in combination with a high 'resistance fuse having lat one end a lezxible, low-resistanee terminal strap permanently clamped thereto and assing through said'well 'to the exterior of t e plug body, together with a shell contact screwing on the threads of the insulating body oil-the plug and mechanically and .electre cally engaging the projecting I'end of said ruse terminal strap.

.2. A A:fuse plug having a chambered insulating body, a center contact at the entering end of the plug-body and having a receivinnP terminala progecting inward inte the et said burly, and a 'fuse ar- 'tact having a low-resistance terminalprojecting inward into the chamber yof said body, in combination with a high-resistance fuse .having one end clamped to the terminal of said center contact and having a lows resistance flexible terminal strap clamped to its other end and projecting outward through the well in the plug body into mechanical and electrical engagement with the screw shell contact.

4. In a fuse, a fuse unit comprising a flexible high resistance fuse strap and low resistance readily deformable terminals-permanently united thereto by interlocking oilsets of both the fuse strap and terminal elements. y v

5. In a fuse plug, a fuse unit comprising a high-resistance fuse and independent .lowresistance terminals clamped to its opposite ends, one of said terminals being readily deformable to accqommodat'e itself to the threads of the plug.

I6. A Jfuse plug having center and shell contacts and a fuse element connected solelyT by a permanent clamping engagement with said center and shell contacts of the plug.

7. .In a fuse, a fuse unit comprising a flexible highresistance fuse strap and low resistance readily deformable terminals permanently united thereto by interlocking ofi"- sets of both the fuse strap and terminal elements, together with a fuse body of insulat ing material, and ,screw shell and center contactelements thereon directly connected to the fuse terminals solely by clamping engagement therewith, substantially as described.

8. In a fuse plug. a fuse unit comprising a high-resistance fuse element and independent low-resistance terminals permanently clamped to the opposite ends thereof,

one of said.terminals being a flexible strap adapted to be engaged bythe shell contact of the plug. i

9. In a fuse plug, a fuse unit comprising a high-resistance fuse element and low-resistance terminals permamently clamped to the opposite ends thereof, one of said terminals being a center contact rivet.

10. In a fuse plug, a fuse unit comprising ahigh-resistance fuse element and low-resistance terminals permanently clamped to the opposite ends thereof, one of said terminals being a flexible strap adapted to be engaged by the shell contact of the plug, and

body of the strap`the end of the 'fuse .is

permanently confined and readily clamped.

12. In a fuse plug, a fuse strip having at one end a shell terminal comprising a flexible strap having a flange between which and the body of the strap the end of the fuse is permanently confined and readily clamped.

13. In a fuse plug, a chambered insulating body exteriorly-shouldered and threaded at its entering end and recessed to afford a passage opening from the interior to said threaded area, a shell contact screwing on said threaded area and abutting against said exterior shoulder,l in combination with a high-resistance fuse having vpermanently secured thereto at one end an independent flexible low-resistance terminal passing out through said well and engaged between said screw shell and shoulder.

14. In a fuse plug, a chambered insulating-body exteriorly shouldered and threaded at its entering end and recessed to afford a passage opening from the interior to said threaded area, a shell contact screwing on said threaded area and abutting against said exterior shoulder, in combination with a high-resistance fuse having permanently secured thereto at one endan independent flexible low-resistance terminal passing out through said well and overlying certain of the threads'on the exterior of the plug body against which it is clamped by the screw shell.

15. In a fuse plug, a chambere'd insulating` body exteriorly shouldered at its outer or head end, threads formed on said body between, said head and the inner or entering end of the plug, said body being recessed to afl'ord a passage' opening from the interior to the exterior thereof between said shoulder and the entering end of the plug, a shell contact screwing on said threaded area and abutting against said shoulder in combination with a high resistance fuse having permanently'secured thereto at one end a flexible low resistance terminal passing out through said passage and engaged between said shoulder and the abutting end of the screw shell.

ltd

mined points to insure en exact length of said fuse element between said teixnineie, one of said terminals constituting e center centeet rivet.

18. ln a plug fuse, :t high resistance fuse element and low resistance terminale secured to the opposite ends thereof at pre determined points to insure :in exact length of seid fuse el'enient between said terminals, one of seid terminals constituting an independent low resistance sti'ep mechanically and electrically connected te seid fuse and readily deformable into nndnleiens by the pressure of a, sorew shell tei'ini'nal on the and holding seidcentei Contact pla/te 'rigidly in position, e low resistance terminal seemed te the .opposite end sei-d fuse eleigeeegeee ment a predetermined distance "from the center Contact ifiveti the said terminal being engaged and coniined by the screw shell Contact of the plug.

` 20. A fuse comprising a, ehambered insulatng body9 a cap permanently secured in position on said body to @lese said chamber, an exterior screw lshell threaded on said body ai', its entering end and permanently xed in postien, a low esistenee center contact element at the enteiing end of the fuse body, in combine/tion with ay high iesistanee fuse m'iengfed Within the chamber of said body, and having one end permanently secured to the low resistance center Contact element, and its other end permanently cured to a ,low i'esistance exible strep clamped between the shell eontztet and the body of tite plu-g, Substantially es desciibed.

ln testlmony whereof l have signed my neme to this speeieatien,

GILEERT W. GODRDGE. 

